Several types of wound closure devices and methods are known, and typically include sutures, staples, surgical tapes and tissue adhesives. Application of most of these wound closure devices is time consuming, and requires considerable manual dexterity and patience. In addition, while these methods are functionally adequate, some may take too long to provide effective wound closure, or be cosmetically unappealing.
Most prevalent is the use of needles and sutures. Sutures provide high tensile strength, a low incidence of reopening, and can provide minimal cosmetic scarring. Application of sutures is by far the slowest method of obtaining wound closure, the sutures typically require removal and the use of anesthetic and have the highest tissue reactivity and application cost.
Surgical staples have the advantages of rapid application, low tissue reactivity, low cost, and reduced risk of needle-sticks (and hence transmission of blood borne disease) to the surgeon and attending staff. Staples generally have low tensile strength than sutures, generally must be removed, and may interfere with certain imaging modalities, such as MRI or CT scanning. In addition, because staples typically present smaller contact areas to the tissue being closed, they present a higher risk of the wound being torn open.
Surgical tapes provide the least tissue reactivity, rapid application, low infection rates and low cost, reduced risk of needle-sticks, and a high degree of patient comfort. Because such tapes are topically applied, they provide much lower tensile strength than sutures, and thus the highest incidence of inadvertent reopening. In addition, such tapes generally cannot be used in hairy body areas, and must be kept dry.
Tissue adhesives and sealants offer advantages of rapid application, low cost, and a high degree of patient comfort. In addition, such adhesives do not need to be removed. Drawbacks associated with tissue adhesives include low tensile strength and high incidence of wound reopening when applied in areas subject to high tensile loads.
Most biologically derived sealants adhere to tissue by participating in the normal clotting cascade. Fibrin glues, for example, are generally used to control bleeding or to reinforce suture or staple lines rather than to make tissues adhere, thus functioning more as hemostatic agents than glues. While several new technologies are under development that offer the potential for use in diffuse bleeding sites, fibrin glues generally are most effective in areas of inactive bleeding.
Drawbacks common to many previously known wound closure techniques, such as sutures and staples, typically involve the skin in one way or another and therefore cause disfigurement of the skin (i.e. the suture penetration points). In addition, because such devices only hold the tissue together at certain points, they do not take advantage of the entire tissue surface area to create a strong bond.
Drawbacks associated with tissue adhesives and sealants are that most of these glues take several minutes to set, may not work in a wet environments and provide only limited tensile strength. Such glues work by binding with individual molecules on either side of the wound and therefore recruiting a large surface area in the act of binding the two surfaces together. This is an improvement over the needle and suture method where discrete “points” or tracks defined by the puncture sites of the needle where the suture passes through or the puncture site of the staple have the role of providing support for the coaptation of the two surfaces.
In view of the foregoing, it would be desirable to provide wound closure devices and methods that merge the desirable features of previously known wound closure systems, i.e. to take advantage of the entire surface in coaptation as well as utilizing a mechanical element to retain the tissue portions in apposition.
It further would be desirable to provide wound closure devices and methods that allow a surgeon to close a wound rapidly and effectively without damaging the skin surface adjacent the wound, thus creating a scar.
It also would be desirable to provide wound closure devices and methods that provide a high-tensile strength bond and are not visible from outside the skin.
It still further would be desirable to provide wound closure devices and methods that may be used not only to establish and retain tissue portions in apposition, but which also may be used to provide adhesion to a large surface area, e.g., such as for hernia repair or attaching large skin grafts onto the surface of the body.
It also would be desirable to provide wound closure devices and methods wherein the devices may be configured in different shapes for different applications, including such shapes as a sheath, a cylinder, a ball a strip or a long rod like shape, and may be used intraoperatively or laparoscopically.
It yet further be desirable to provide wound closure devices and methods that can be used in wet or bleeding environments without significant loss of intended function.
It also would be desirable to provide wound closure devices that can be doped with a therapeutic agent, e.g., growth factor or thrombin, to aid wound healing or a clot enhancement.